Hyperkalemia

Definition

98% of total body potassium is intracellular
Gradient maintained by
- Na-K antiporters (3Na:2K)
- H-K antiporter
Normally excreted in the urine
- Aldosterone stimulates ENAC channels and Na-K channels

Decreased excretion
- Decreased aldosterone
  - Primary adrenal insufficiency
  - Secondary adrenal insufficiency
    - ACE inhibitors
    - Angiotensin-receptor blockers
    - Renin inhibitors
    - NSAIDs
    - Congenital adrenal hyperplasia
- Decreased aldosterone responsiveness
  - Spironolactone
  - Amiloride
- Decreased sodium delivery to kidneys
  - Hypovolemia
  - Heart failure
  - Cirrhosis
  - Nephrotic syndrome
Increased intake
- Iatrogenic
Shifts
- Rhabdomyolysis
- Tumour lysis syndrome
- Acidosis
- Drugs
  - Hypoinsulinemia
  - Beta blockers
  - Digoxin
  - Succinylcholine
- Hemolysis
- Anemia
- Increased plasma osmolality
Factitious
- Hemolysed samples
- Increased white cell count
  - Chronic lymphocytic leukemia
- Increased platelets

EKG
Repeat serum potassium
Pharmacologic treatment indicated if EKG changes
Stabilize
- Calcium gluconate 1g IV push q30min prn EKG changes
  - Lasts 30-60 minutes
  - Repeat EKG in 30 minutes, then can give another 1g
Shift
- Insulin R 10 unites in 1 amp D50W
- Albuterol 8-10 puffs
- Bicarbonate
  - No evidence of benefit and increases serum sodium
Excrete
- Kayexalate and lactulose
  - Takes 2-3 days to work
- Normal saline
- If not hypovolemic and not on ACEi or ARB, furosemide
- If refractory to medical management, dialysis